The navigation progress sometimes can not work common

[312362115]

• (void)backItemAction { if ([self.navigationController isShowingProgressBar]) { [self.navigationController cancelProgress]; [self.navigationController setProgress:0 animated:NO]; } [self.navigationController popViewControllerAnimated:YES]; }

I use navigation progress in a webView, it works. but sometimes, when I pop back, the navigation progress will not cancel or finish. The prev viewcontroller will show the progress. It happened sometimes.